Downloadedfrom …38 Keywords: sled training, sled towing, potentiation, 1080 Sprint, horizontal...

Dow

nloadedfrom

https://journals.lww.com

/nsca-jscrbyBhD

Mf5ePH

Kav1zEoum1tQ

fN4a+kJLhEZgbsIH

o4XMi0hC

ywCX1AW

nYQp/IlQ

rHD3p1zuFA1M

WB3aLdW

pIoFOIq6FxD

5h+Hkw

R2m

T+LQNgC

VhuKgMr3T23Q

==on

01/24/2019

Downloadedfromhttps://journals.lww.com/nsca-jscrbyBhDMf5ePHKav1zEoum1tQfN4a+kJLhEZgbsIHo4XMi0hCywCX1AWnYQp/IlQrHD3p1zuFA1MWB3aLdWpIoFOIq6FxD5h+HkwR2mT+LQNgCVhuKgMr3T23Q==on01/24/2019

Journal of Strength and Conditioning Research Publish Ahead of PrintDOI: 10.1519/JSC.0000000000002524 Resisted Sprints in Varsity Level Sprinters -

Moderate Load Resisted Sprints Do Not Improve Subsequent Sprint Performance in Varsity 1

Level Sprinters 2

3

Kyle M.A. Thompson1, Alanna K. Whinton1, Shane Ferth1, Lawrence L. Spriet1, Jamie F. Burr1 4

5

1Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada 6

7

Corresponding Author 8

Jamie F. Burr 9

University of Guelph, HHNS 10

ANNU, 50 Stone Road East 11

Guelph, ON, Canada, N1G 2W1 12

Tel: 1-519-824-4120 ext. 52591 13

Fax: 1-519-763-5902 14

Email: [email protected] 15

16

This research was supported by a Mitacs Accelerate grant, in collaboration with the Speed River 17

TFC. (IT08409) 18

19

ACCEPTED

Copyright ª National Strength and Conditioning Association 2018

Resisted Sprints in Varsity Level Sprinters -

Abstract 20

Resisted sprint training (RST) is commonly used for performance enhancement in athletics and 21

team sports to develop acceleration ability. Evidence suggests that RST may be effective as a 22

short-term intervention to improve successive sprints. While these improvements have been 23

measured in team sport athletes, limited research has considered the acute effects of RST training 24

in sprint-trained athletes. Therefore, the aim of the current study was to determine if performing 25

RST with varsity level sprinters using sled-equivalent resistive loads of ~45% body mass results 26

in a potentiation effect, leading to improvements in subsequent maximal sprint performance over 27

0-5 m and 0-20 m. Competitive sprinters (n=20), were randomly assigned to perform a pre/post 28

maximal 20 m sprint separated by either 3 resisted (RST group) or un-resisted (URS group) 29

sprints. The RST or URS protocol was performed on four occasions separated by at least 7 days. 30

No significant differences were observed between the RST and URS groups comparing changes 31

in sprint times over 0-5 m (URS ∆ = <0.01 s ± 0.03 s, RST ∆ = <0.01 s ± 0.03 s) and 0-20 m 32

(URS ∆ = 0.013 s ± 0.04 s, RST ∆ = <0.01 s ± 0.04 s). We conclude that resisted sprints using 33

sled equivalent loads of 45% body mass are ineffective at inducing a potentiating effect on 34

subsequent sprint performance in varsity level sprinters. In this population of trained athletes, 35

greater loads may be necessary to induce a potentiating effect. 36

37

Keywords: sled training, sled towing, potentiation, 1080 Sprint, horizontal power, acceleration 38

39

ACCEPTED



INTRODUCTION 40

The ability to accelerate is essential for athletic performance in both individual and team sports 41

(3). Sprint acceleration is a result of both horizontal and vertical power production, which can be 42

increased through changes in sprint mechanics (21) or by increasing lower limb muscle 43

mass/strength (1,26). These modifiable characteristics are, therefore, targeted by coaches aiming 44

to improve acceleration ability. Contrast training and resisted sprint training (RST) emphasize 45

the use of these types of specific strengthening exercises, which can ultimately improve 46

horizontal power production, leading to enhanced acceleration. 47

48

Contrast training involves a muscular overloading exercise, which precedes an outcome exercise 49

such as sprinting, jumping, or throwing (23). Heavy back squats (>90% 1 repetition maximum 50

(RM)) and depth jump exercises are most commonly employed as overloading stimuli and are 51

believed to elicit a post-activation potentiation response (11,25). Post-activation potentiation is a 52

physiological phenomenon believed to cause myosin regulatory light chains to become 53

phosphorylated, leading to an increased sensitivity of actin and myosin to calcium, which 54

theoretically allows for greater strength and speed performance (11,25). Whether it be related to 55

the effects of post-activation potentiation, or another performance-enhancing mechanism, 56

improved sprint performances have been reported following overload exercises (16). Resisted 57

sprint-training (i.e. sprinting while pulling a weighted sled) can be considered an acceleration 58

specific contrast training protocol because it offers the ability to overload muscles in similar 59

positions required during an unloaded acceleration, without significantly altering sprint 60

ACCEPTED



mechanics (22). This specificity is vital to improving outcome exercise performance (unloaded 61

sprinting), as performing a conditioning exercise that uses similar joint angles to the outcome 62

exercise results in the greatest transfer effect (7,11,20). Resisted sprint training studies lasting 4 – 63

8 weeks (2,15,17,18,27) have reported changes in stride length, stride frequency and ground 64

contact time, while acute responses to resisted sprints such as increases in horizontal force 65

production have been demonstrated (14). 66

67

Few studies have examined the potentiating effect of resisted sprints in highly-trained subjects, 68

and of those that exist, protocol variations such as: running surface, harness attachment site, 69

temporal pattern of data collection within athletes’ training season, measurement error, and 70

subject characteristics contribute to inconsistent outcomes within and between studies. Two 71

recent investigations using trained rugby athletes have shown improvements in sprint 72

performance after very heavy resisted sprints (24,30). Improved sprint performance in these 73

studies contrasts with an earlier study by Whelan et al. (28), who found no enhancement in sprint 74

performance following moderate load resisted sprints (25-30% body mass) in physically active, 75

but non-specifically trained men. Comparing these studies, the difference in outcome may be 76

attributed to the resisted sprint load or subject variability due to the subject’s training status. In 77

the study by Whelan et al., which used lighter loads (26), the inter-trial and inter-individual 78

variability of the participants may have masked performance benefits. That is, a true effect of 79

moderate-load sprinting (if it occurred) may have been undetectable, owing to the large 80

variability about the mean changes. This is particularly likely in un-trained runners who would 81

ACCEPTED



have a relatively high variability that may overshadow small, but potentially meaningful changes 82

in sprint performance. Alternatively, the heavy resisted sprint loads used by Seitz et al. (24) and 83

Winwood et al. (30) of 75% body mass may be necessary to induce changes in sprint 84

performance. Although, it is unclear if this load is universally required to elicit a potentiation 85

response in all subjects, or if it is only appropriate for rugby union athletes, who train for the 86

specific demands of a strength-dominant sport. If the resisted sprint load necessary to induce a 87

potentiation effect is dependent on the subjects’ training focus, it is possible that lighter loads 88

may be suitable in populations that focus more on speed of movement, such as sprinters. 89

Additionally, recent work by Jarvis et al. (13) has shown that a lighter load of ~50% body mass 90

was effective at improving subsequent sprint performance in varsity level team sport athletes. 91

92

Therefore, with a group of highly trained sprinters, it was hypothesized that inter-sprint 93

variability would be extremely low, allowing any observed changes in performance to be 94

attributed to the resisted sprint intervention. A small, but meaningful, change in sprint 95

performance was expected following the moderate load (~45% body mass sled equivalent load) 96

resisted sprint intervention, as recent work has shown improvements in sprint performance 97

following similar loads. 98

99

ACCEPTED



METHODS 100

Experimental Approach to the Problem 101

A randomized control experimental design with an un-resisted sprint control group (URS, n=10) 102

and intervention group (RST, n=10) was used to determine the post-exposure effects of resisted 103

sprint-training on subsequent 0-5 m and 0-20 m sprint performance. Inter-sprint variance of the 104

subjects was initially determined, to ensure changes in performance could be confidently 105

attributed to the intervention. Testing of both the URS and RST subjects was conducted during 106

the subjects’ competitive season to ensure high-level performances during all trials. Subjects 107

were randomly assigned to either the URS or RST group for four testing sessions. In order to 108

evaluate the effectiveness of a moderate resistive load (~45% body mass sled equivalent load) 109

the resistive loading parameters of the 1080 Sprint device used in the current study were 110

mathematically matched based on previous work (19). The mathematical matching of the 1080 111

Sprint resisted load to a sled equivalent load was necessary, as the 1080 Sprint resistance is not 112

dependent on sprint surface coefficient of friction, is unidirectional (horizontal) and remains 113

constant during the entire sprint duration. 114

115

Subjects 116

Twenty track and field sprinters (male=11, female=9) who had previous experience with 117

resistance training, sprint-training, and resisted sprint-training using traditional weighted sleds 118

were recruited for the study (age = 20 ± 2 years, female body mass = 59 ± 6 kg, male body mass 119

ACCEPTED



= 76.1 ± 7.8 kg) (Table 1). Subjects were excluded if their primary indoor track event was ≥300 120

m. In addition to the acceleration training days during which data was collected, subjects 121

completed 2-3 resistance training sessions, one maximal velocity sprint session, and one work 122

capacity sprint session per week. This additional training was consistent among all subjects. The 123

protocol was approved by the research ethics committee at the sponsoring university, and written 124

informed consent was obtained from all subjects prior to testing. 125

[INSERT TABLE 1. HERE] 126

Procedures 127

1080 Sprint Resistance and Data Collection Tool 128

All data was recorded using a 1080 Sprint device (1080Motion, Sweden), which uses a robotic 129

flywheel resistance and simultaneously records velocity, power, horizontal force, distances and 130

time. The error of the 1080 Sprint has previously been examined and is low across all 131

measurements (velocity error = ± 0.5%, distance error = ± 5 mm, force error = ± 4.8 N) (4). 132

Subjects attached a harness to their waist from which a tether cord was run to the 1080 Sprint 133

device. Baseline and final sprints were measured using the “isotonic” function of the 1080 Sprint 134

with the minimum functional load of 1 kg, which is required to maintain tension on the cord. 135

Given that a minimal resistive load is required for the device to function and this is the first study 136

to simultaneously use the 1080 Sprint as a training and data collection tool, we performed fifty 137

sprint trials while measuring 0-10 m, 10-20 m and 20-30 m splits concurrently with a Freelap 138

timing system (Freelap, California, USA), a Stalker Pro II Radar system (Applied Concepts, 139

Texas, USA) and the 1080 Sprint (1080Motion, Sweden) to determine the similarity between 140

ACCEPTED



each timing device. This comparison was performed to allow for sprint times obtained using 141

timing gates or radar timing systems to be compared to the sprint times obtained in the current 142

study. 143

144

Determining Population Variability 145

Thirty unloaded sprint trials were used to determine typical inter-sprint variability within a 146

varsity level sprint-trained subject. Subjects performed 3 maximal 20 m sprints from sprint 147

blocks, in track spikes, on an indoor polytan track surface, with outcomes measured using the 148

1080 Sprint device. Data was stored online for later analysis. This protocol was performed on 149

two separate days to determine individual within and between day inter-sprint variation. 150

Testing Protocol 151

Subjects performed five maximal 20 m sprints. The first was used as the baseline sprint, 152

following which, subjects in the RST group performed three resisted sprints (Sprint 2 - Sprint 4), 153

while subjects in the URS group performed three un-resisted sprints. Sprint 5 was the final sprint 154

and was un-resisted for both groups. A minimum of 3 min was given between each sprint to 155

ensure full recovery while not exceeding the 10 min time span in which an acute performance 156

enhancing effect is likely to be observed following a potentiating stimulus (29). Subjects 157

performed either the RST or URS protocol on four separate occasions to account for daily 158

fluctuations in performance. 159

160

ACCEPTED



Statistical Analysis 161

Pearson correlations and the coefficient of variation (CV) was used to compare and characterize 162

the difference between the 1080 Sprint, Freelap and Stalker Pro II Radar timing systems. A 163

factorial 2(Group) x 2(Test) x 4(Day) repeated measures ANOVA was used to compare baseline 164

and final sprint times for the RST and URS groups. A t-test was used to compare both the 165

changes in step rates and changes in average horizontal force production. An alpha level of 166

p<0.05 was selected, a priori. As previously stated, a magnitude-based inferences approach was 167

concurrently used to account for changes in performance which may have been missed using 168

null-hypothesis testing. The CV of the testing population was determined using a sub-group of 169

sprinters as described above, and the smallest worthwhile change (SWC) in performance was 170

determined for 5 m and 20 m sprints using 0.2 of the group standard deviation (12). Results are 171

presented as mean ± SD. 172

173

RESULTS 174

Sprint times obtained using the 1080 Sprint, Freelap and Stalker Pro II Radar timing systems 175

were practically identical (Table 2). No significant changes in sprint times over 0-5 m (∆ URS = 176

-0.003 s ± 0.03 s, RST ∆ = 0.0008 s ± 0.03 s, p=0.63) or 0-20 m (URS ∆ = -0.01 s ± 0.04 s, RST 177

∆ = -0.003 s ± 0.04 s, p=0.33) were observed in either the RST or URS groups (Figure 1). No 178

changes in step rate (0-5 m p=0.32, 0-20 m p=0.20) or average horizontal force production (0-5 179

m p=0.28, 0-20 m p=0.56) were observed over 0-5 or 0-20 m following the RST intervention. 180

Average individual CV was 1.82% (~0.02 s) at 0-5 m and 1.19% (~0.04 s) over 0-20 m. The 181

ACCEPTED



SWC in performance for 0-5 m was 0.01 s and it was 0.03 s over 0-20 m. The mean group 182

change in performance did not exceed the SWC after performing the RST intervention over 0-5 183

m or 0-20 m. Therefore, RST using moderate loads did not improve post-exposure sprint 184

performance in highly trained sprinters after being analyzed using a null-hypothesis or 185

magnitude-based inferences statistical approach. 186

[INSERT TABLE 2. HERE] 187

[INSERT FIGURE 1. HERE] 188

DISCUSSION 189

We sought to examine whether resisted sprints using a moderate load could induce a 190

performance enhancing effect in sprint-trained subjects over 0-5 m and 0-20 m. The methods 191

were designed such that inclusion criteria selected for highly trained sprinters to minimize 192

between-sprint variation and all testing was performed during the subjects’ competitive season to 193

ensure maximal effort during all trials. Trials were completed at an indoor training facility on a 194

high quality polytan track surface, limiting extraneous and variable environmental factors. 195

Additionally, a 1080 Sprint device was employed for resistive loading and sprint characteristic 196

measurement, which improves future replicability and ensures all resistive loads remained 197

constant. Since the 1080 Sprint is controlled electronically using a robotic flywheel system, the 198

resistance applied during the sprint is highly reliable and quantifiable; as opposed to weighted 199

sleds wherein the resistive load can change substantially depending on the coefficient of friction, 200

which varies with the track surface, sled runner quality, and sled velocity (19). Finally, in 201

addition to the study criteria meant to reduce these limitations, a parallel magnitude-based 202

ACCEPTED



statistical approach was included as a form of analysis. The use of this approach has become 203

increasing popular in the field of sport performance research, as it is not biased by statistical 204

power and allows for subjects within a population to be assessed individually against both their 205

own previous performances and a predetermined “meaningful” change (5). A strong argument 206

for the use of this analysis when examining highly trained subjects who may expect to see 207

relatively small changes as a result of an intervention has been made previously (5,10,12). 208

209

A major strength of the current study was the highly-trained nature of the participants. With an 210

average individual CV over 5 m and 20 m sprints of less than 2%, subjects repeatedly achieving 211

sprint times within 0.04 s. Thus, even if a small effect occurred, it would have been detected. 212

This consistency is similar to the variation (~2%) seen in professional athletes used in other 213

training studies (8) and is an essential quality often neglected in the field of sprint research which 214

allows outcomes to be confidently attributed to the intervention under examination. No 215

performance enhancing effect was observed following the RST intervention over 0-5 m or 0-20 216

m. Step rate and horizontal force production were further analyzed to characterize sprint 217

characteristics. As expected, based on the lack of change in sprint times, no changes in either 218

step rate or force production was observed. This outcome is consistent with the results of Whelan 219

et al. (28) who showed no acute enhancement of sprint velocity after performing resisted sprints 220

in physically active men using a slightly lighter load of 25-30% body mass. Therefore, even 221

when ensuring consistent loading parameters, using subjects with low inter-sprint variability and 222

analyzing data with a statistical approach specifically designed to evaluate changes in this type of 223

ACCEPTED



scenario, we do not observe changes in sprint performance following moderate load resisted 224

sprints (~45% body mass sled equivalent load). 225

226

The lack of change in sprint performance following the current intervention may suggest that a 227

greater resistive load is necessary to induce an acute potentiation effect. Although the resisted 228

sprint literature has historically refrained from using resistive loads greater than ~40% body 229

mass due to the belief that heavy loads may negatively impact sprint mechanics, two recent 230

studies have assessed the performance enhancing ability of resistive sprint with loads as high as 231

150% body mass (24,30). Both studies reported improvements in sprint times over 15-20 m after 232

performing weighted sled sprints with ~75% body mass loads but decrements in sprint 233

performance when using loads of 125% and 150% body mass (24,30). Both groups also used 234

trained rugby athletes as their subjects, making it plausible that the 75% body mass loads were 235

optimal for this population due to the strength-oriented nature of their training. A previous 236

investigation of post activation potentiation suggests that stronger individuals (1 RM squat >160 237

kg) have a greater improvement in vertical jump performance (+4.01%) compared with those 238

who had a 1RM squat of < 160 kg (+0.42%) following a potentiating protocol (9). This suggests 239

that subjects must have a specific baseline strength to benefit from a potentiating protocol, and 240

was a rationale for our hypothesis that lighter loads may yet be effective for sprinters, who 241

possess explosive power, but are not typically defined as strength-based athletes per se. 242

243

ACCEPTED



While strength status may play a contributing role in potentiation ability, new research focusing 244

on determining optimal loading parameters for maximal horizontal power may provide an 245

alternative perspective. Using both recreational and elite level sprinters, Cross et al. (6) very 246

recently demonstrated that both populations produced maximal horizontal power at resistive 247

loads of ~80% body mass. If these loads consistently allow subjects of various athletic 248

backgrounds to achieve maximal horizontal power, perhaps the potentiating effect seen by 249

Winwood (30) and Seitz et al. (24) was a result of their subjects performing sprints in this 250

optimal zone, rather than their strength status. This would indicate that performing resisted sprint 251

training as a potentiation technique requires athletes to use loads of ~80% body mass, or more 252

specifically, loads which allow the individual to produce maximal horizontal power. To 253

accommodate both potential explanations of how resistive sprint loads of ~80% body mass 254

improve sprint performance, future research should incorporate strength testing into their design 255

to categorize subjects based on strength levels while additionally monitoring whether subjects 256

are producing their maximal horizontal power. 257

258

Sled equivalent resisted sprint loads of ~45% body mass using a 1080 Sprint do not elicit an 259

immediate performance enhancing effect in varsity level sprinters. Athletes with highly 260

reproducible results, such as the sprint-trained athletes used in the current investigation, offer the 261

greatest chance of observing small, but meaningful, alterations in performance and are 262

recommended for future investigations in this area. Future research should also determine 263

ACCEPTED



whether performing resisted sprints with a load that allows subjects to achieve maximal 264

horizontal power is the determining factor when desiring a performance enhancing effect. 265

266

PRACTICAL APPLICATIONS 267

Sprint-trained athletes are capable of highly reproducible results, and are thus optimally suited 268

for examining potentially small changes in sprint performance. The results did not support the 269

hypothesis, that a potentiation effect would be observed following resisted sprints with moderate 270

loads. Therefore, it is not recommended that coaches use these loading parameters (45% body 271

mass sled load) as an acute performance enhancing method. Findings from Jarvis et al. (13) 272

currently suggest that a minimal load of 50% body mass should be considered if trying to 273

structure resisted sprints within the warm-up to acutely enhance sprint performance during 274

competition. We also showed that the 1080 Sprint device can be used as a reliable timing system 275

while simultaneously being used as a training tool. The 1080 Sprint is therefore, a viable 276

research and training tool for researchers and coaches to accurately control resisted sprint 277

training loads while measuring other commonly evaluated sprint characteristics such as sprint 278

time, horizontal force production, step rates, sprint velocity and horizontal power. 279

ACKNOWLEDGEMENTS 280

The authors thank the athletes who participated in the study and the coaches for their time. This 281

study was supported by a Mitacs Accelerate grant, in collaboration with the Speed River TFC 282

(IT08409). The authors declare no conflict of interest. 283

284

ACCEPTED



REFERENCES 285

1. Aerenhouts, D, Delecluse, C, Hagman, F, Taeymans, J, Debaere, S, and Van Gheluwe, B. 286

Comparison of anthropometric characteristics and sprint start performance between elite 287

adolescent and adult sprint athletes. Eur J Sport Sci 12: 9–15, 2012. 288

2. Alcaraz, PE, Elvira, JLL, and Palao, JM. Kinematic, strength, and stiffness adaptations 289

after a short-term sled towing training in athletes. Scand J Med Sci Sport 24: 279–290, 290

2014. 291

3. Baker, DG and Newton, RU. Comparison of lower body strength, power, acceleration, 292

speed, agility, and sprint momentum to describe and compare playing rank among 293

professional rugby league players. J Strength Cond Res 22: 153–158, 2008. 294

4. Bergkvist, C, Svensson, M, and Eriksrud, O. Accuracy and Repeatability of Force, 295

Position and Speed Measurement of 1080 Quantum and 1080 Sprint. 2015. 296

5. Buchheit, M. The Numbers Will Love You Back in Return — I Promise. Int J Sport 297

Physiol Perform 11: 551–554, 2016. 298

6. Cross, MR, Brughelli, M, Samozino, P, Brown, SR, and Morin, J-B. Optimal Loading for 299

Maximising Power During Sled-resisted Sprinting. Int J Sports Physiol Perform 1–25, 300

2017. 301

7. Fletcher, IM. The Effect of Different Dynamic Stretch Velocities On Jump Performance. 302

Eur J Appl Physiol 109: 491–498, 2010. 303

ACCEPTED



8. Fletcher, IM and Jones, B. The Effect of Different Warm-Up Stretch Protocols on 20 304

Meter Sprint Performance in Trained Rugby Union Players. J Strength Cond Res 18: 885–305

888, 2004. 306

9. Gourgoulis, V, Aggeloussis, N, Panagiotis, K, Mavromatis, G, and Garas, A. Effect of a 307

submaximal half-squats warm-up program on vertical jumping ability. J Strength Cond 308

Res 17: 342–344, 2003. 309

10. Haugen, T and Buchheit, M. Sprint Running Performance Monitoring: Methodological 310

and Practical Considerations. Sport Med 46: 1–16, 2015. 311

11. Hodgson, M, Docherty, D, and Robbins, D. Post-activation potentiation: Underlying 312

physiology and implications for motor performance. Sport Med 35: 585–595, 2005. 313

12. Hopkins, WG, Marshall, SW, Batterham, AM, and Hanin, J. Progressive statistics for 314

studies in sports medicine and exercise science. Med Sci Sports Exerc 41: 3–12, 2009. 315

13. Jarvis, P, Turner, A, Chavda, S, and Bishop, C. The acute effects of heavy sled towing on 316

subsequent sprint acceleration performance. J Trainology 6: 18–25, 2017. 317

14. Kawamori, N, Newton, R, and Nosaka, K. Effects of weighted sled towing on ground 318

reaction force during the acceleration phase of sprint running. J Sports Sci 32: 1139–1145, 319

2014. 320

15. Kawamori, N, Newton, RU, Hori, N, and Nosaka, K. Effects of weighted sled towing with 321

heavy versus light load on sprint acceleration ability. J Strength Cond Res 28: 2738–2745, 322

2014. 323

ACCEPTED



16. Linder, EE, Prins, JH, Murata, NM, Derenne, C, Morgan, CF, and Solomon, JR. Effects of 324

preload 4 repetition maximum on 100-m sprint times in collegiate women. J Strength 325

Cond Res 24: 1184–1190, 2010. 326

17. Lockie, RG, Murphy, AJ, Schultz, AB, Knight, TJ, and Janse de Jonge, XK. The Effects 327

of Different Speed Training Protocols on Sprint Acceleration Kinematics and Muscle 328

Strength and Power in Field Sport Athletes. J Strength Cond Res 26: 1539–50, 2012. 329

18. Makaruk, B, Sozański, H, Makaruk, H, and Sacewicz, T. The Effects of Resisted Sprint 330

Training on Speed Performance in Women. Hum Mov 14: 116–122, 2013. 331

19. Cross MR, Tinwala, F, Lenetsky, S, Samozino, P, Brughelli, M, and Morin, J-B. 332

Determining friction and effective loading for sled sprinting. J Sport Sci 0: 1–6, 2016. 333

20. Miyamoto, N, Mitsukawa, N, Sugisaki, N, Fukunaga, T, and Kawakami, Y. Joint angle 334

dependence of intermuscle difference in postactivation potentiation. Muscle and Nerve 41: 335

519–523, 2010. 336

21. Morin, JB, Gimenez, P, Edouard, P, Arnal, P, Jiménez-Reyes, P, and Samozino, P. Sprint 337

acceleration mechanics: The major role of hamstrings in horizontal force production. 338

Front Physiol 6: 1–14, 2015. 339

22. Petrakos, G, Morin, JB, and Egan, B. Resisted Sled Sprint Training to Improve Sprint 340

Performance: A Systematic Review. Sport. Med. 46: 381–400, 2016. 341

23. Seitz, LB and Haff, GG. Factors Modulating Post-Activation Potentiation of Jump, Sprint, 342

Throw, and Upper-Body Ballistic Performances: A Systematic Review with Meta-343

ACCEPTED



Analysis. Sport Med , 2015. 344

24. Seitz, LB, Mina, MA, and Haff, GG. A sled push stimulus potentiates subsequent 20-m 345

sprint performance. J Sci Med Sport , 2017. 346

25. Seitz, LB, Trajano, GS, Haff, GG, Dumke, CC, Tufano, JJ, and Blazevich, AJ. 347

Relationships between maximal strength, muscle size, myosin heavy chain isoform 348

composition and post-activation potentiation. Appl Physiol Nutr Metab 497: apnm-2015-349

0403, 2016. 350

26. Sleivert, G and Taingahue, M. The relationship between maximal jump-squat power and 351

sprint acceleration in athletes. Eur J Appl Physiol 91: 46–52, 2004. 352

27. Spinks, C, Murphy, A, Spinks, W, and Lockie, R. The Effects of Resisted Sprint Training 353

on Accceleration Performance and Kinematics in Soccer, Rugby Union, and Australian 354

Football Players. J Strength Cond Res February: 77–85, 2007. 355

28. Whelan, N, O̓Regan, C, and Harrison, AJ. Resisted sprints do not acutely enhance 356

sprinting performance. J Strength Cond Res 28: 1858–1866, 2014. 357

29. Wilson, JM, Nevine M. Duncan, Pedro J. Marin, Lee E. Brown, Jeremy P. Loenneke, 358

Stephanie M.C. Wilson, Edward Jo, RPLA, and Ugrinowitsch, C. Post activation 359

potentiation: A meta analysis examining the effects of volume, rest period length, and 360

conditioning mode on power. Med Sci Sport Exerc 44: 86–87, 2012. 361

30. Winwood, P, Posthumus, LR, Cronin, JB. The acute potentiating effects of heavy sled 362

pulls on sprint performance. J Strength Cond Res 30: 1248–1254, 2016. 363

ACCEPTED


Resisted Sprints in Varsity Level Sprinters - Page 1

Table 1. Subject Characteristics within the Resisted Sprint Training and Un-Resisted Sprint groups.

Subject Characteristics RST URS Age (y) 20.6 ± 2.3 19.7 ± 1.6 Number of Subjects M/F

6 / 5

5 / 4

Mass M/F (kg)

75.4 ± 8.7 / 61.2 ±4.4

75.4 ± 8.7 / 58.8 ± 7.3

Best time over 60m M/F (s)

6.75 - 7.24 / 7.59 - 7.77

6.87 - 7.19 / 7.62 - 8.04

ACCEPTED



Table 2. Comparative sprint analysis between 1080 Sprint, Freelap timing gate system and Radar system.

0-10m 10-20m 20-30m

Freelap - 1080 Sprint

Pearson Correlation 0.87 0.99 0.98 Coefficient of Variation %/s

4.75 (0.002s)

2.03 (0.003s)

2.19 (0.007s)

Radar - 1080 Sprint

Pearson Correlation 0.87 0.94 0.99 Coefficient of Variation %/s

5.11 (0.015s)

4.32 (0.008s)

1.51 (0.002s)

ACCEPTED



Figure 1. Changes in Sprint Time Over 0-5m and 0-20m

Individual differences between baseline (Sprint 1) and final (Sprint 5) sprint times over 5 m (a.) and 20 m (b.). Individual points represent an average change in sprint time for subjects over the four trials with error bars representing individual SD. A meaningful change in performance was determined to be 0.01 s over 0-5 m and 0.03 s over 0-20 m.

-0.0

8-0

.06

-0.0

4-0

.02

0.00

0.02

0.04

0.06

0.08

INDIVIDUAL 5m PRE/POSTU

RS

Sub

ject

sR

ST

Sub

ject

s

-0.1

0-0

.08

-0.0

6-0

.04

-0.0

20.0

00.0

20.0

40.0

60.0

8

UR

S S

ubje

cts

RS

T S

ubje

cts

INDIVIDUAL 20m PRE/POSTa. b.

ACCEPTED


Downloadedfrom …38 Keywords: sled training, sled towing, potentiation, 1080 Sprint, horizontal...

Documents

Transcript of Downloadedfrom …38 Keywords: sled training, sled towing, potentiation, 1080 Sprint, horizontal...